Muffler.



P. M. FREER.

MUFFLER.

APPLICATION FILED APR. 11, I916.

RENEWED MAY 2!.1917.

Patented Feb. 5, 1918.

Gwynne/13S UNITED STATES PA PHELPS M. FREEZE, 0F DETROIT, MICHIGAN.

MUFFLER.

Specification of Letters Patent. '7 I. Patented Feb. 5,- 1918.

Application filed April 17, 1916, Serial No. 91,663. Renewed myariiz. Serial No. 170,083.

To all whom it may concern:

Be it known that I, PHELPS M. FREER, a citizen of the United States of America, residing at Detroit, in the countyv of Wayne and State of Michigan, have invented certaln new and useful Improvements in Mufiiers, of which the following is a specification, reference being had therein to the accompanying drawings.

The invention relates to mufilers designed for use upon internal combustion engines which are provided with fans for the cooling system. It is the object of the invention to utilize the fan for dissipating the exhaust gases, and the latter for increasing the efliciency of the fan, as hereinafter set forth.

In the drawings:

Figure l is a longitudinal section through the fan housing and muffler;

Fig. 2 is a transverse section.

A is the rotary shaft, on which is mounted the fan B, within a spiral casing C having a tangential discharge D, the arrangement being such that air which is drawn in laterally is swept around by the fan blades and out through the tangential discharge. E is a casing surrounding the spiral fan casing and forming a tapering exhaust discharging nozzle, the discharge end of which enters the fan casing in the direction of the rotation of the fan. The exhaust from the engine intermittently enters this casing E through the port F at the end thereof, and after passing therethrough is discharged into the air current. Thus with each exhaust impulse a high velocity is imparted to the gases which are discharged through the tapering nozzle, which will operate to accelerate the movement of the air within the fan casing; and on the other hand, when the exhaust pressure is relieved the suction of the fan will draw upon the gases to accelerate movement thereof. In other words, the moving body of air acts as an equalizer for the exhaust discharge, preventing any recoil or collapse after the exhaust pressure is relieved and thereby eliminating noise.

In addition to regulating the velocity of discharge of the exhaust gases the fan performs the further function of dissipating heat therefrom, and thereby etfecting aquick lowering of the temperature and condensation in volume. This is due to the fact that the airwhich is handled by the fan is of much lower temperature than the exhaust gases, and on account of. its contact with the peripheral wall of the. spiral casing, it will maintain said wall also at a comparatively low temperature. Thus the exhaust gases entering the tapering chamber will be cooled by this peripheral wall and will be contracted in volume, so that thesmall discharge end will not materially impede or interfere with the velocity of movement.

The device may also be so constructed as to increase the efficiency of the fan. For this purpose the spiral casing C is provided at intervals with openings G, with defiectors H so arranged that a small portion of the air propelled around the casing will enter the surrounding casing E and will be commingled with the exhaust gases. Whenever the velocity of the exhaust exceeds that of the air in the fan, air will be drawn out ward through the ports G and finally discharged at a higher velocity through the small end of the nozzle, where it will again operate to accelerate the movement of the air. The total effect is to increase the amount of air that is handled by the fan.

My improved construction is particularly applicable to engines of the type in which the cylinders revolve around the crank shaft and exhaust into a surrounding casing. As shown in Fig. 1, this casing I is connected by a plurality of ports J to an annular casing K adjacent thereto, which casing communicates with the port F. This permits the exhaust from successive cylinders to pass through the same ports, all combining to maintain the velocity of movement of gas through the tapering casing E.

What I claim as my invention is 1. In an engine, the combination with a rotary fan and a casing inclosing the same, of a tapering exhaust conduit surrounding said casing and discharging thereinto at its small end.

2. The combination with a rotary fan having a lateral inlet and tangential discharge.

of an exhaust conduit surrounding said fan and casing and discharging tangentially into 5 casing being provided With a plurality of tangential openings into said exhaust conduit, for the purpose described.

5. In an engine, the combination With a rotary fan having a tangential discharge, of

an exhaust conduit connected to and extending partially around the casing of said fan i to discharge in the direction of rotation thereof.

6. In an internal combustion engine, the

combination with means for propelling a cooling air current, of means for dischargthe exhaust from the engine into said air current after the same has passed through said propelling means.

7. In an engine, the combination with a rotary air propelling fan having a tangential discharge, of an exhaust conduit partially surrounding the fan casing and discharging into the column of air after the same'has passed through said fan.

8. In an engine, the combination With a rotary fan and a casing containing the same, of an exhaust conduit surrounding said casing and discharging thereinto into the air discharged from said fan in the direction of movement of said air.

In testimony whereof I aflix my signature.

PHELPS M. FREER. 

